ASSERT: A physician-in-the-loop content-based retrieval system for HRCT image databases

It is now recognized in many domains that content-based image retrieval fro m a database of images cannot be carried out by using completely automated approaches. One such domain is medical radiology for which the clinically u seful information in an image typically consists of gray level variations i n highly localized regions of the image. Currently, it is not possible to e xtract these regions by automatic image segmentation techniques. To address this problem, we have implemented a human-in-the-loop (a physician-in-the- loop, more specifically) approach in which the human delineates the patholo gy bearing regions (PBR) and a set of anatomical landmarks in the image whe n the image is entered into the database. To the regions thus marked, our a pproach applies low-level computer vision and image processing algorithms t o extract attributes related to the variations in gray scale, texture, shap e, etc. In addition, the system records attributes that capture relational information such as the position of a PER with respect to certain anatomica l landmarks. An overall multidimensional index is assigned to each image ba sed on these attribute values. (C) 1999 Academic Press.